RFR: 456: Read value of resolved in build properly when considering backports

[Robin Westberg]

Hi all,

Please review this small change that makes sure that the JBS custom field "resolved in build" is read properly.

Best regards,
Robin

-------------

Commit messages:
 - It's non-null values that cause problems
 - Add missing null check

Changes: https://git.openjdk.java.net/skara/pull/706/files
 Webrev: https://webrevs.openjdk.java.net/skara/706/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-456
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/skara/pull/706.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/706/head:pull/706

PR: https://git.openjdk.java.net/skara/pull/706